Polaroids And Karo Syrup


Beautiful and simple demonstration of optical activity.


Goose neck lamp with 100 watt bulb, rotating polaroids on base, bottle of Karo syrup with label removed.




Place a glass bottle of Karo syrup between two crossed polaroids lighted from behind, then rotate one of the polaroids. The second polarizing sheet removes a small band around one wavelength of light, to produce beautiful negative colors. This is a breathtaking experiment for those seeing it the first time. A must with this topic. See the Feynman Lectures text for a nice explanation.


W. P. Healy and E. A. Power, Dispersion Relations for Optically Active Media, AJP 42, 1070-1074 (1974). R. M. Peterson, Comparison of two theories of optical activity, AJP 43, 969-972 (1975).